This invention relates to a method for producing eggs containing a high amount of iodinated amino acids.
Eggs are generally known as highly nutritive and well balanced digestible and absorbable food. Recently, however, a sharp controversy has been raised about the cholesterol contained in eggs. Namely, one opinion is that egg eaters are prone to develop heart trouble, whereas another opinion is that there is no causal relation between heart diseases and the cholesterol in eggs. It is reported that as result of such controversy, a number of U.S. consumers are cutting down on their daily egg consumption. For this reason or not, egg consumption has also tended to lessen in Japan recently.
We, inventors, have studied ways of improving the composition of the egg, and have finally discovered that hens fed with a large amount of calcium iodate Ca(IO.sub.3).sub.2 lay eggs containing a higher amount of iodinated amino acids, although the cholesterol content of the egg does not change. We also found that the eating of the said eggs does not increase the amount of cholesterol in the blood, that is to say, haematic cholesterol. On the contrary, it was ascertained by us that the eating of said eggs decreases the amount of haematic cholesterol in the case of a patient suffering hypercholesteremia.
There is seldom reported a deficiency disease of iodine in Japan, since the Japanese people usually eat seaweed containing a large amount of iodine. On the other hand, the people of inland areas of Asia and America suffer from iodine deficiency, and make up for the deficiency by taking iodized salt, namely, common salt admixed with potassium iodide (KI).
Iodine is one of the mineral requirements for hens. The National Research Council specifically has set the demand amount of iodine for hens at about 0.3 mg. per kg. of feed. An example of actual admixture of potassium iodide in feed is reported in "Poultry Science," Vol. XXV, No. 2, March 1946, p 99-104, "The Use of Various Vitamin Supplements in Rations for Laying and Breeding Hens" which reveals the addition of 0.005% potassium iodide or about 2% iodized salt to a ration. Addition of 5 g. iodized salt per kg. of feed is also mentioned in U.S. Pat. No. 3,982,008. Furthermore, it is stated in "Hackh's Chemical Dictionary" McGraw-Hill Book Co., N.Y., 1969, p 354, that iodized salt contains about 0.3% of potassium iodide. In all of the cases, the substance to be added is potassium iodide, and the addition amount is 0.5 mg. to 60 mg. per kg. of feed. It has been ascertained through our study that adding of potassium iodide at such a level is only effective in maintaining the hen's health. It was also proven that addition of potassium iodide over said amount is not a useful method, because the rate of egg laying of hens tends to decrease.